This invention relates to a new group of compositions that are useful in preventing nylon and wool fiber and fabrics made from them, including carpeting and upholstering materials, from being permanently stained by food colors contained in foods spilled on the fiber. This new group of sulfomethylated phenol-formaldehyde or naphthol-formaldehyde and anionic surfactant compositions not only block the stain from adhering to the fiber but also minimize any yellowing or discoloration which ultimately deteriorates the lightfastness typically caused by phenol-formaldehyde or naphtol-formaldehyde condensates.
Heretofore, fibers were treated with acid dye fixing agents, such as INTRATEX.RTM.N, to block the dyeing sites on the fiber. This type of sulfonated phenol-formaldehyde condensates prevented the fibers from becoming "dyed" with the food colors, such as FD&C Red 40 in KOOL-AID.RTM.. Additionally, flurocarbon finishes such as ZEPEL.RTM. and SCOTCHGUARD.RTM. are known to repel water-borne and oil-borne stains, and are usually applied after dyeing, unless they are built into the greige fiber. These finishes, however, do not afford a satisfactory protection against food colors, which is the reason for using Food Color Stain Blocking Agents in addition to the fluorocarbon Finishes.
INTRATEX N, as many other such fixing agents, tend to slightly yellow or discolor the fiber while affecting, at the same time, its lightfastness. This fact alone limits the amount which can be applied to the fiber, since the amount of yellowing is in direct proportion to the percent of active ingredient exhausted onto the fiber, and this limiting amount is frequently not sufficient to produce the desired stainblocking effect.
Likewise, fibers have been treated with anionic surface active agents such as CENEGEN.RTM.7. These surfactants afford little stain blocking ability to the treated fibers but cause minimal yellowing with no deleterious effects on the lightfastness of the fibers at concentrations of about 0.5%-3.0%.
U.S. patent application Ser. No. 07/064,856 filed June 19, 1987 teaches the use of a group of sulfonated phenol formaldehyde or naphthol formaldehyde condensates and anionic surfactant compositions to prevent nylon and wood fibers, and fabrics made from them, including carpeting and upholstery materials, from being permanently stained by food colors contained in foods spilled on the above materials.
In practicing the above art in textile mills, it is frequently preferred, when applying the compositions, to use soluble alkaline earth salts, especially magnesium sulfate (due to its relatively low cost and ample availability), most often in the form of Epsom Salts, in order to achieve a complete exhaust, or full deposition of said compounds from the treatment bath onto the substrate being treated. The reason for this practice is to achieve the most complete possible utilization of the stain blocking compound for economic reasons as well as for environmental reasons, i.e. to keep chemicals content of the effluing bath to a minimum.
Unfortunately many of the above stainblocking agents are not stable or their stability is shortlived with magnesium sulfate and with other alkaline earth metal salts, in acid conditions. In such cases the treatment bath must be discarded before its complete utilization, and a new one prepared.
This problem is overcome by formulating the said stain blocking agents, such as the group of products of U.S. patent application Ser. No. 07/064,856, file June 19, 1987, with the acid forms of anionic surface-active agents, included in the above U.S. patent application.
Thus, an acid stable stainblocking agent can be made within the parameters of the prior art including sulfonated phenol-formaldehyde or naphthol formaldehyde condensation products. Unfortunately, in the process of formulating the above compositions with the free acid form of the anionic surface active agents, it is necessary to use relatively high amounts of solvents, such as diglycols, glycol ethers, and other hydroxylated solvents, in order to keept he resulting product storage-stable in the form of a homogeneous solution. In addition, this formulation adjustment adds too many inactive ingredients diluting the stainblocking activity of the product.